Page 43 - TNFlipTest

Toronto Notes 2019 Airway Management
Tube Insertion
• laryngoscopyandETTinsertioncaninciteasignificantsympatheticresponseviastimulationofcranial nerves 9 and 10 due to a “foreign body reflex” in the trachea, including tachycardia, dysrhythmias, myocardial ischemia, increased BP, and coughing
• amalpositionedETTisapotentialhazardfortheintubatedpatient
■ if too deep, may result in right endobronchial intubation, which is associated with left-sided
atelectasis and right-sided tension pneumothorax
■ if too shallow, may lead to accidental extubation, vocal cord trauma, or laryngeal paralysis as a result
of pressure injury by the ETT cuff
• thetipofETTshouldbelocatedatthemidpointofthetracheaatleast2cmabovethecarinaandthe
proximal end of the cuff should be placed at least 2 cm below the vocal cords
■ approximately 20-23 cm mark at the right corner of the mouth for men and 19-21 cm for women
Confirmation of Tracheal Placement of ETT
• direct
■ visualization of ETT passing through cords
■ bronchoscopic visualization of ETT in trachea
• indirect
■ ETCO2 in exhaled gas measured by capnography – a mandatory method for confirming the ETT is
in the airway
■ auscultate for equal breath sounds bilaterally and absent breath sounds over epigastrium
■ bilateral chest movement, condensation of water vapour in ETT visible during exhalation and no
abdominal distention
■ refilling of reservoir bag during exhalation
■ CXR (rarely done): only confirms position of the tip of ETT and not whether the ETT is in the
trachea
• esophagealintubationsuspectedwhen:
■ ETCO2 zero or near zero on capnograph
■ abnormal sounds during assisted ventilation
■ impairment of chest excursion
■ hypoxia/cyanosis
■ presence of gastric contents in ETT
■ breath sounds heard when auscultating over epigastrium/LUQ ■ distentionofstomach/epigastriumwithventilation
Complications During Laryngoscopy and Intubation
• dentaldamage
• laceration (lips, gums, tongue, pharynx, vallecula, esophagus)
• laryngealtrauma
• esophagealorendobronchialintubation
• accidentalextubation
• insufficientcuffinflationorcufflaceration:resultsinleakingandaspiration • laryngospasm (see Extubation, A20, for definition)
• bronchospasm
Difficult Airway
• difficultieswithbag-maskventilation,supraglotticairway,laryngoscopy,passageofETTthroughthe cords, infraglottic airway or surgical airway
• algorithmsexistfordifficultairways(CanJAnesth2013;60:1119-1138;Anesthesiology2003;98:3273; Anesthesiology 2013;118:251-270), see Appendices, A30
• pre-operativeassessment(historyofpreviousdifficultairway,airwayexamination)andpre-oxygenation are important preventative measures
• ifdifficultairwayexpected,consider:
■ awake intubation
■ intubating with bronchoscope, trachlight (lighted stylet), fibre optic laryngoscope, glidescope, etc.
• ifintubationunsuccessfulafterinduction:
1. CALL FOR HELP
2. ventilate with 100% O2 via bag and mask
3. consider returning to spontaneous ventilation and/or waking patient
• ifbagandmaskventilationinadequate: 1. CALL FOR HELP
2. attempt ventilation with oral airway 3. consider/attempt LMA
4. emergency invasive airway access (e.g. rigid bronchoscope, cricothyrotomy, or tracheostomy)
Anesthesia A9
Differential Diagnosis of Poor Bilateral Breath Sounds after Intubation
DOPE
Displaced ETT Obstruction Pneumothorax Esophageal intubation
Cormack-Lehane Classification of Laryngeal View (Figure 3)
• Grade 1: all laryngeal structures revealed
• Grade 2: posterior laryngeal 2A (posterior
vocal folds) 2B (arytenoids)
• Grade 3: Larynx concealed, only epiglottis
• Grade 4: Neither glottis nor epiglottis
Predicting Difficult Intubation in Apparently Normal Patients
Anesth 2005;103:429-437
Purpose: To assess widely available bedside tests and widely used laryngoscopic techniques in the prediction of difficult intubations.
Study: Meta-analysis.
Patients: 35 studies encompassing 50,760 patients. Definitions: Difficult intubation was defined usually as Cormack–Lehane grade of 3 or greater, but
some authors reported the requirement of a special technique, multiple unsuccessful attempts, or a combination of these as the accepted standard for difficult intubation.
Results: The overall incidence of difficult intubation was 5.8% (95% CI 4.5-7.5%) for the overall patient population, 6.2% (95% CI 4.6-8.3%) for normal patients excluding obstetric and obese patients, 3.1% (95% CI 1.7-5.5%) for obstetric patients, and 15.8% (95% CI 14.3-17.5%) for obese patients Mallampati score: SN:49% SP:86% PLR:3.7 NLR:0.5; thyromental distance: SN:20% SP:94% PLR:3.4 NLR:0.8; sternomental distance: SN:62% SP:82% PLR:5.7 NLR:0.5; mouth opening: SN:22% SP:97% PLR: 4.0 NLR:0.8; Wilson risk-sum: SN:46% SP:89% PLR:5.8 NLR:0.6; combination Mallampati and thyromental distance: SN:36% SP:87% PLR:9.9 NLR:0.6.
Conclusions: A combination of the Mallampati score and thyromental distance is the most accurate at predicting difficult intubation. The PLR (9.9) is supportive of the test as a good predictor of difficult intubation.
PLR: positive likelihood ratio; NLR: negative likelihood ratio; SN: sensitivity; SP: specificity
If you encounter difficulty with tracheal intubation, oxygenation is more important than intubation